The performance of flexible fluid–structure interaction module for saltmarsh vegetation under flow and wave action

Abstract

This paper evaluates the performance of a new flexible fluid–structure interaction (FSI) module in an open-source computational fluid dynamics (CFD) software—REEF3D—for use in modelling saltmarsh vegetation. Unlike previous studies, which focussed on hydrodynamic response to plants (for example, wave attenuation) to check the accuracy of their numerical modelling efforts, this work attempts to replicate the plants’ drag force and motion behaviour, based on results from several physical modelling studies. The flexible FSI module was found to consistently overestimate both the drag and motion of the numerical plants when compared to their physical counterparts. It is hypothesized that this is due to the module’s use of linearly elastic material theory for the flexible structures. This is arguably inadequate for the relatively flexible materials of saltmarsh vegetation.